Preliminary studies indicate that schizophrenic illness with late life onset shows both important similarities and differences compared to more typical cases with onset in early life. We propose to examine the structural and dopamine D2 receptor brain changes associated with late life onset schizophrenia using MRI, CT and PET scanning. C-11 labelled N-methyl Spiroperidol will be used as the PET ligand. This, in conjunction with modelling studies, will yield Bmax values of dopamine D2 receptors. Bmax changes will be compared to those previously reported to accompany normal aging and those found in early life onset schizophrenia. Suitable control groups will be examined. These will consist of elderly normal volunteers and currently elderly early life onset schizophrenics, matched for age, sex, and race with the late life onset schizophrenics. Structural brain and receptor changes will be analyzed to determine their association with clinical symptomatology, neuropsychologic abnormalities, sensory deficits, and social factors. This may aid understanding of late life onset schizophrenia, and clarify the relationship of this syndrome both to early onset cases and to the psychopathology of aging.